About Moisture Meters
A moisture meter is a device which is used to measure the percentage of water in a substance. It can be used in various ways, from helping to determine whether a building is suffering from damp, to measuring the moisture content of a concrete screed to see whether it is ready to receive a floor covering, to checking firewood to measure if it is dry enough to burn cleanly.
Available is a wide range of moisture meters, both used and new, from various brands such as iXium, Maplin, Rapitest, Tramex, SmartBurn and Silverline. Some are professional quality devices such as those used by surveyors, whereas others are aimed at anyone who would like to use it for domestic purposes such as checking their firewood to ensure it is dry enough to use.
There are two main methods of measuring water content with moisture meters; resistance and capacitance. Resistance, or pin, meters are still the most commonly used type. These have two or more pins which are pushed into the substance being tested. An electrical current is emitted by one pin and is then picked up by the other. The wetter the material, the more efficiently the current passes as moisture is a good conductor. The meter then reads how much resistance there is to the current and effectively correlates this reading to the moisture content. EMW or electromagnetic wave meters are capacitance meters which emit electrical waves via a sensor pressed against the substance being tested. These create an electromagnetic field which behaves differently according to the level of moisture.